Mechanical tuning peg for stringed instruments



Dec. 24, 1968 K. s. CLARK MECHANICAL TUNING PEG FOR STRINGED INSTRUMENTSFiled Dec. 8. 1967 INVENTOR IIIIIII KENNETH S. CLARK av ATTYS.

United States Patent 3,417,647 MECHANICAL TUNING PEG FOR STRINGEDINSTRUMENTS Kenneth S. Clark, 300 (Jroyden Road, Cheltenham, Pa. 19012Filed Dec. 8, 1967, Ser. No. 689,060 6 Claims. (Cl. 84-305) ABSCT OF THEDISCLOSURE The present invention relates generally to tuning pegs forstringed instruments such as violins, violas, and cellos and relatesmore particularly to a tuning peg for such instruments which has aninternal locking device, such pegs being known as mechanical pegs.

The tuning of stringed instruments is generally accomplished byadjusting the tension of the individual strings.

In instruments such as violins, violas and cellos, the string tension isadjusted by means of tuning pegs which extend through aligned holes inthe spaced walls of a peg box in the head of the instrument. In thetraditional peg design, the peg shafts are tapered approximately twodegrees to permit the frictional securing of the pegs in l the similarlytapered peg holes when the string has been tuned to the desired tension.However due to the tension of the strings and the vibrations of theinstrument, the pegs gradually slip from their adjusted position,necessitating a frequent retuning of the instrument.

To alleviate the tuning bur-den of conventional pegs, various mechanicalpegs have been developed which have an internal mechanism for lockingthe peg in the peg box. Although several types of mechanical pegs havebeen developed, they have for the most part been characterized bycomplicated devices which require special tools and usually the servicesof a skilled craftsman to mount in an instrument. Prior mechanical pegshave generally been expensive to manufacture due to their complexity. Inaddition, there has been a danger with some pegs of cracking the peg boxof the instrument by overtightening the pegs. Furthermore, some types ofmechanical pegs cannot be manufactured with the traditional pegappearance.

In the present invention, a mechanical peg is provided of a simple,economical design having a minimum number of parts. The peg is adaptedto lock both radially and axially against a bushing which may beinserted into the peg box of a conventional instrument without specialtools. In brief, the present peg comprises a peg head and a stringholder which are secured in axially opposed relation against the sidesof the bushing by an axial screw. The screw passes through a tubularmetal insert anchored axially within the peg head, and is threaded intoa similar insert axially anchored in the string holder, each of theinserts extending in close fitting relation into an axial bore of thebushing. The ends of the inserts within the bushing engage alongcomplementary beveled surfaces whereby rotation of the peg head causesrotation of the string holder. Upon tightening of the locking screw, thebushing is gripped axially by the peg head and string holder, and inaddition the beveled surfaces of the inserts 3,417,647 Patented Dec. 24,1968 provide an internal expansion of the inserts against the bore ofthe bushing to provide a radical locking force.

It is accordingly a first object of the present invention to provide amechanical tuning peg for stringed instruments of a simple, economicaldesign which provides a positive locking effect without endangering theintegrity of the instrument.

A further object of the invention is to provide a tuning peg asdescribed which may be easily mounted in a conventional instrumentwithout special tools.

Another object of the invention is to provide a tuning peg as describedwhich has the traditional appearance of a tapered friction peg.

A still further object of the invention is to provide a tuning peg asdescribed which may be fabricated largely of molded plastic materials.

Still another object of the invention is to provide a tuning peg asdescribed which, with a single screw adjustment, provides both an axialand a radial gripping force on a bushing inserted into the instrumentpeg box.

Additional objects and advantages of the invention will be more readilyapparent from the following detailed description of an embodimentthereof when taken together with the accompanying drawings in which:

FIG. 1 is a perspective view of the head of a stringed instrumentshowing a mechanical tuning peg in accordance with the present inventionmounted therein;

FIG. 2 is a partial enlarged sectional view taken along line 22 of FIG.1 showing the details of the tuning peg;

FIG. 3 is an exploded perspective view showing the several components ofthe tuning peg of FIGS. 1 and 2; and

FIG. 4 is an enlarged partial sectional view schematically showing thelocking forces developed against the tuning peg bushing upon thetightening of the peg locking screw.

Referring to the drawings, and particularly FIG. 1 thereof, the head 10of a stringed instrument such as a violin, viola or cello is illustratedincluding the string fingering board 12, peg box 14 and scroll 16. Thepeg box 14 includes spaced walls 18 and 20 having aligned pairs of pegholes 22 arranged in spaced relation therein. In the conventionalinstrument shown, the peg holes 22 are tapered to receive thetraditional tapered pegs which have a two degree taper to provide africtional seating of the pegs. Since the pegs are normally arranged ina staggered manner with two peg heads extending on each side of theinstrument, the peg holes are tapered accordingly.

The instrument head 10 is conventional in every respect and requires nomodification to accept the present mechanical tuning pegs. The presentpeg, generally designated 24, as shown in FIG. 3 comprises prior toinstallation four separable components, the string holder 26, bushing28, peg head and the peg locking screw 32. The peg head 30 includes athumb piece 34 and a shank portion 36 having a slightly taperingcylindrical surface. As shown in FIG. 2, in their assembled relation,the outer surfaces 38 and 40 respectively of the string holder 26 andbushing 28 form a continuation of the tapering outer surface of theshank 36 of the peg head. The taper should be approximately two degreesto permit the peg to fit without special adaptation into the peg holes22 of a conventional instrument.

The peg head 30 is preferably formed of a plastic material such as highimpact styrene and has molded therewithin a metal tubular insert 42extending axially therethrough. The insert 42 is knurled at 44 andincludes an annular groove 46 to prevent rotational and axial movementof the insert with respect to the peg head. The

insert 42 terminates at its outer end 48 in. flush relation with the endof the thumb piece 34 and at its inner end extends beyond the shankportion 36 in a projecting portion 50, terminating in a beveled surface52.

The string holder 26 similarly is made in the preferred embodiment of amolded plastic such as styrene and includes a metal insert 54 axiallymolded partway thereinto. A knurled surface 56 and an annular groove 58on the insert 54 prevent rotational or axial movement of the insertwithin the string holder. The insert 54 extends axially beyond thestring holder 26 in a projecting portion 60 which terminates in abeveled surface 62 complementary to the surface 52 of the peg headinsert 42. The insert 54 has a threaded coaxial bore 64 which is adaptedto receive the threaded locking screw 32. The locking screw passes witha slight clearance through the tubular insert 42 of the peg head 30. Thescrew head 66 of the locking screw in the assembled peg seats againstthe outer end 48 of the insert 42 and includes a slot 68 for adjustmentby means of a screw driver or thin coin.

The bushing 28 includes an annular bore 70 which should be of a diameteronly slightly greater than the outer diameter of the projecting portions50 and 60 of the inserts 42 and 54 to permit a snug fit of the insertstherewithin. The bushing includes a pair of wedge-like securing fins 72for anchoring the bushing against rotation within the peg box wall. Inorder to conceal the bushing from view, it should have an axialdimension equal to the thickness of the peg box wall. The bushing ispreferably made of the same plastic material as the peg head and thestring holder, and a preferred material for this purpose as indicatedabove is high impact styrene.

For installation of the present mechanical peg in a conventionalinstrument of the type illustrated in FIG. 1, the string holder insertprojecting portion 60 is inserted into the bore 70 of bushing 28 and thetwo components are inserted into one of the pairs of aligned peg holesof the instrument, the smaller end 74 of the string holder fitting intothe smaller of the tapered peg holes. The bushing is press fitted intothe larger of the aligned holes, the securing fins 72 locking thebushing in place against rotational forces. The fins 72 should be quitesmall to avoid damage or defacing of the instrument upon insertion ofthe bushing. The fins should actually be somewhat smaller thanillustrated in the drawings, their size in the drawings beingexaggerated for purposes of illustration.

The peg head 30 is positioned with the projecting portion 50 of theinsert 42 extending into the bore 70 of the bushing 28 so that thecomplementary beveled surfaces 52 and 62 of the inserts 42 and 54 are incontact as illustrated in FIG. 2. The locking screw 32 is then screwedinto the threaded bore 64 of insert 54 and the installation is complete.In the instrument illustrated in FIG. 1, only one of the pegs 24 hasbeen installed for simplicity of illustration although it is apparentthat the three additional pegs would be installed in the same manner.

For operation, a string 76 of the instrument is passed at the upper endof the fingering board 12 over the string guide 78 and through a stringhole 80 in the string holder 26. A knot is placed in the string tosecure it in the string hole. With the locking screw 32 loosenedslightly from its tightened position, the string is tuned by turning thethumb piece 34 to achieve the correct string tension. The beveledsurfaces 52 and 62 of inserts 42 and 54 are held in contact by the screw32 and provide a rotation of the string holder 26 with the peg head 30.

To lock the peg in the desired position, the locking screw 32 istightened, causing the double acting locking effect illustratedschematically in FIG. 4. The end faces of the string holder and theshank portion of the peg head should engage the bushing simultaneouslywith the engagement of the complementary beveled surfaces of the insertsas the tightening of the locking screw is begun. In View of therelatively non-compressible character of the inserts as contrasted withthe plastic material of the string holder, bushing, and peg head, afurther tightening of the screw results in a radial displacement of theinserts to produce a radial locking force at the same time that theaxial locking force is applied to the bushing. Since the projectingportions of the inserts fit snugly within the bore of the bushinginitially, only a slight radial displacement of the projecting insertportions, in the order of a few thousandths of an inch, is required toexert a substantial locking force radially against the bushing bore. Theclearance between the locking screw 32 and the bore of tubular insert 42need be only about six thousandths of an inch to permit this lockingforce, and, in view of its small size, cannot be seen in the drawings.

While the angle of the beveled surfaces 52 and 62 has been illustratedas 45 in the preferred embodiment, this angle may be varied depending onthe relative degree of radial expansion force desired. Similarly,although metal such as steel is the preferred material for the insertsand locking screw, and molded plastic such as high impact styrene ispreferred for the string holder, peg head and bushing, other materialsmay suitably be employed. For example, the string holder, bushing andpeg head may be made of wood or a wide variety of synthetic materialsincluding nylon. Although the cost would be high, it would be possibleto form the string holder and insert as well as the peg head and itsinsert as unitary metal elements.

By use of the present invention, the tuning of the instrument strings isrequired only at infrequent intervals and in many instances can beaccomplished by adjustment of a fine tuning device (not shown) at thelower end of the string. The present invention is particularly adaptedfor use with students who initially have difliculty in properly tuningthe instrument. The device is also of importance to accomplishedmusicians such as orchestra personnel and soloists who no longer areforced to hastily retune an instrment in the midst of a performance.

Although the present invention is shown illustrated in the setting of adouble walled peg box, the invention can also 'be adapted for use withinstruments such as guitars and banjos wherein the peg passes through asingle peg board. For such applications, the axial length of the stringholder is substantialy shortened.

I claim:

1. A mechanical tuning peg for a stringed instrument comprising, abushing adapted for fixed mounting in the instrument, a string holderand a peg head disposed on opposite sides of said bushing, a projectingportion of said string holder extending into the bore of said bushingand terminating therewithin in a beveled surface, a projecting portionof said peg head extending into the bore of said bushing and terminatingin a beveled surface complemetary to and in engagement with the beveledsurface of said string holder portion, and screw means connecting saidpeg head and said string holder, the tightening of said screw meansproviding an axial locking force on said bushing by said opposed stringholder and peg head as well as a radial locking force provided by saidbevelsurfaced projecting portions.

2. A mechanical tuning peg for a stringed instrument comprising abushing adapted for fixed mounting in the instrument, a string holderand a peg head disposed on opposite sides of said bushing, an internallythreaded insert anchored in said string holder, a projecting portion ofsaid insert extending into the bore of said bushing and terminatingtherewithin in a beveled surface, a tubular insert anchored in said peghead, a projecting portion of said latter insert extending into the boreof said bushing and terminating in a beveled surface complementary t0and in engagement with the beveled surface of said string holder insert,and a locking screw passing through said tubular peg head insert andthreadedly engaged in said string holder insert, the tightening of saidlocking screw providing an axial locking force on said bushing by Saidopposed string holder and peg head as well as a radial locking forceprovided by said bevel-surfaced inserts.

3. A mechanical tuning peg for a stringed instrument such as a violin,viola or cello having a peg box characterized by tapered peg holes, saidpeg comprising a tapered bushing adapted for press fitting into a peghole of the instrument peg box, a string holder and a peg head disposedon opposite sides of said bushing, said string holder having a taperedconfiguration adapted to extend into the peg hole opposite that of saidbushiiig, means on said string holder for attaching a string thereto, aninternally threaded insert anchored in said string holder, a projectingportion of said iinsert extending into the bore of said bushing in closefitting relation and terminating therewithin in a beveled surface, saidpeg head comprising a thumb piece and a shank portion, a tubular insertanchored in said peg head and extending axially through said thumb pieceand shank portion, the shank portion of said peg head having a taperedconfiguration which is an extension of the tapered configuration of saidstring holder and bushing, a projecting portion of said peg head insertextending into the bore of said bushing in close fitting relation andterminating in a beveled surface complementary to and in engagement withthe beveled surface of said string holder insert, and a locking screwpassing through said tubular peg head insert and threadedly engaged insaid string holder insert, the tightening of said locking screwproviding an axial locking force on said bushing by said opposed stringholder and peg head as well as a radial locking force provided by saidbevel-surfaced inserts.

4. A turning peg is claimed in claim 3 wherein said inserts are made ofmetal and wherein said string holder, bushing and peg head are made of amolded plastic.

5. A tuning peg as claimed in claim 3 wherein said bushing includes anaxially aligned wedge shaped locking fin on the tapered surface thereoffor securing the bushing against rotation in the instrument peg hole.

6. A tuning peg as claimed in claim 3 wherein the taper of said peg headshank portion, bushing, and string holder is approximately two degrees.

References Cited FOREIGN PATENTS 280,298 11/1914 Germany.

RICHARD B. WILKINSON,'Primary Examiner.

